Sunlight Natures source of Vitamin D

Posted by Vani Tadepalli on Sun, Oct 20, 2013  
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What is Vitamin D?

Vitamin D is a fat soluble vitamin, which is also considered as a steroid hormone. It is synthesized in the body when skin is exposed to sunlight by UV irradiation of 7-dehydrocholesterol thus adequate exposure to sunlight causes less dietary requirement of Vitamin D.


Sun exposure- The timing matters!

Sun exposure between the hours 10.00AM and 3:00PM in spring, summer and autumn is more when compared to other timing and seasons.


Melanin absorbs UVB photons, so people with more melanin pigmentation require longer exposure compared to light skinned people. Therefore melanin works as a natural sunscreen.


Excess prolonged exposure to sunlight causes skin cancer, melanomas; therefore application of sunscreen has a protection against skin cancers in people who are exposed to direct sunlight for prolonged periods.


Sunscreen’s and effect on Vitamin D synthesis

Sunscreens work by absorbing UVB radiation before it enters skin therefore sunscreen with a sun protection factor (SPF) 8, reduces the capacity of skin to produce vitamin D by more than 95%. Time of the day, season and latitude influence vitamin D synthesis from skin.


Vitamin D- The food sources

Other than sunlight the sources of vitamin D are fish, liver, egg yolk, milk, butter etc.


Why Vitamin-D is important?

Vitamin D primarily plays a role in maintaining calcium homeostasis. Vitamin D production by kidney is increased when calcium levels are low, and it acts concomitantly with Parathormone, which is also produced in response to decreased calcium levels.)


Symptoms of Vitamin D deficiency

Most commonly recognised symptoms of vitamin D deficiency are rickets (decreased mineralization of osteoid matrix and cartilage resulting in soft, pliable bones), Osteomalacia (pre-existing bone is demineralised causing it to be softer and more susceptible to fractures).


Most of dairy products nowadays are fortified with vitamin D, so Rickets and Osteomalacia are very rare and most commonly seen in low-income groups, the elderly (who have minimal exposure to sunlight), strict vegetarians (those who take more fibre diet) and chronic alcoholics.


Vitamin D- Link to Cancers

Recent studies suggest that inadequate vitamin D intake may increase the risk of certain types of cancers (Breast, Colon, and Prostate), Hypertension and Autoimmune diseases (Multiple sclerosis, Rheumatoid arthritis, Crohn’s disease, Type 1 Diabetes Mellitus).


Recommended daily dose of Vitamin D

Required dietary intake of vitamin D is 200IU up to age 50yrs, and from 51-70yrs it is 400IU, and people more than 71yrs require 600IU.adequate sun exposure can reduce the required intake.


Vitamin D deficiency can also result from fat mal absorption or severe liver and kidney diseases and even certain drugs (corticosteroids stimulate the conversion of vitamin D to inactive metabolites and cause bone demineralization when used for longer periods) can interfere with vitamin D metabolism.


So, let us all make it a habit of morning walk to keep us fit and as well helps in providing adequate amount of natural vitamin D through adequate sunlight exposure.


Enjoy a Beach Holiday- Be Healthy

Planning a family holiday to beaches will also provide a good exposure to sunlight but with proper application of sunscreen lotions after 5- 15minutes of sunlight exposure.


Avoid air conditioners and keep windows open, which allow fresh air and sunlight into our houses.


Indulge in good amount of dairy products like cheese, ghee, butter, fish etc to gain adequate dietary vitamin D and keep yourselves free from bone related disorders.


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